Drill



Jan. 15, 1935. J. c. WRIGHT I 1,987,886

DRILL Filed 001,. ll, 1952 .Inventor Patented Jan. 15, 1935 PATENT OFFICE DRILL y Jesse C. Wright, Los Angeles, Calif., asslgnor to Globe Oil Tools Co., Los

ration of California Application October 11,

4 Claims.

This invention relates to drills such as used for drilling in deep wells.

When an ordinary iishtail bit is employed in drilling through hard formation, the progress 5 of the bit is comparatively slow, for the reason that the lower cutting edge of the bit extends in to a point at or near the axis of rotation of the bit, and this part of the cutting edge moves relatively slowly. However, the bit can not progress until the central portion of the hole is cut away. For this reason, bits of the fishtail type are relatively inefficient, and this is true oi all other rotary bits which must remove the earth at the central portion of the hole that the bit is drilling.

Core drills have been employed in whlchl the cutting edge is located in a zone removed from the axis of rotation, but these drills are used generally for taking cores for the purpose of studying a formation through which the drill is passing, and they usually operate to take a core of relatively small diameter, and are constructed as far as possible, to preserve the integrity oi the core that the drill takes. Such core drills are not generally used for regular drilling purposes.

The general object of this invention is`to provide a drill oi improved construction, which operates on a dierent principle from ordinary bits, including core drills, and which will enable a drilling operation to be carried on most eiciently and at a relatively high speed as regards the progress of the bit through hard for,

mation, such as commonly encountered in the drilling of deep oil wells or the like.

A further object of the invention is to produce a drill which will remove a maximum amount of material from the hole, 'with the minimum amount of actual cutting.

A further object of the invention is to produce a drill capable of continuously taking a core of relatively large diameter, and provided with means for continuously washing or scouring away the soft components of the core.

A further object of the invention is to construct the drill with means which will enable a hard core to be engaged and cut off at will, when it is necessary to pull the drill string carrying the tool.

A further object of the invention is to construct a drill in such a way that the core will be subjected to the eroding and washing action of circulating water projected against the core at a relatively high velocity.

A further object of the invention is to provide Nietos, Calif., a corpo- 1932, Serial No. 637,229 (Cl. Z55-72) a drill having features of construction which will facilitate the washing and scouring action of circulating water passed down the drill string,

to expedite the operation of carrying away from the core, of its relatively soft components, in 5 order to increase the period of time in which the tool can operate continuously without filling the core chamber in which the hard core material accumulates.

Further objects of the invention will appear hereinafter.

Regarding the invention as a mechanical improvement, the invention consists in the novel parts and combination ci parts, all of which contribute to producing an emcient drill for l5 deep wells.

A preferred embodiment ci the invention is described in the following specication, while the broad scope of the invention is pointed out in the appended claims. 20

ln the drawing, Figure l is a side elevation and partial elevation oi a drill embodying my invention, certain parts being broken away;

Figure 2 is a horizontal section taken on the line 2 2 of Figure l;

Figure 3 is a bottom plan of the drill, and particularly illustrating details of the invention;

Figure e is a vertical section taken through the upper end of a drill, embodying this inven= tion, and illustrating means which l may ems ploy for' supporting a core-holder or guide;

Figure 5 is a fragmentary view and correspends to Figure l, but illustrating details oi a type oi core-cutting tool which I may employ for cutting into a hard core just before the drill string is to bev pulled;

Figure 6 is a view similar to Figure 5, but il-v lustratingthe co-operative action of the corecutting tools illustrated in Figure 5;

Figure '7 is a view similar to Figures 5 and 6, but illustrating another type of core-cutting tool which I may employ for performing this function.

Before proceeding to a more detailed` description of the invention, it should be stated that in accordance with my invention, I employ a rotary 4 core drill which is rotated to cut through the formation so as to take a core preferably of relatively large diameter; while this core is being taken, I subject it to the severe scouring action of water passing down through the drill string, and 5 thereby I disintegrate and wash away the loose earth and relatively soft components of the core, leaving only the relatively hard or rocky parts of the core within the drill.

The drill is constructed to take a core of atively large diameter, much larger than obtains in the use of standard core-taking drills, and the cutters on the shoe of the tool which cut through the formation, do not extend into the axis of the tool, but cut an annular zone considerably removed from the axis of rotation. For this reason, the length of the cutting edge of the tool is relatively small, giving a relatively great weight or load upon the cutting edge for each unit of its length. For this reason, the tool cuts relatively rapidly through hard formation. The tool is constructed so that circulating water passes down through it as the drilling progresses, and features of the tool operate to develop a high velocity in the circulating water as it is projected against the side of the core, thereby washing away the relatively soft portions of the core.

The tool is provided with means for facilitating thorough irrigation of the core by the circulating water, and is also provided with means for enabling a hard core to be readily cut away when desired, by the operation of the tool, to enable the core to be disengaged from the formation, and withdrawn with the drill when the drill 4string is pulled.

If desired, a core guide or centering means is employed for facilitating circulation of the water alongside of the core, thereby preventing any possibility of the core becoming packed in the drill to such an extent as would enable it to impede or choke off the free movement of the circulating water.

Referring more particularly to the parts, and particularly to Figure 1, 1 indicates the drill body which preferably consists of a piece of drill tubing, the lower end of which may be secured by threads 2 in a sub 3. This sub carries a drill shoe 4. It should be understood, however, that while I prefer to construct the drill of these separate parts, in practice if desired, the sub and the shoe 4 could readily be formed as one piece.

The upper end of the body l is provided with an upper sub 5, which is provided with suitable means such as a tapered, threaded pin 6, for enabling the same to be attached to a tubular drill string having the usual bore for conducting circulating water down to the passage '7 in the sub 5. The shoe 4 is provided with any suitable means for cutting out a zone of earth or formation when the tool is rotated on its vertical axis, and so that the tool will leave an uncut core to be receivedin the body `1 of the tool as it progresses downwardly.

The shoe 4 is preferably constructed so that the core which it takes, will be of considerably smaller diameter than the inside diameter of the body or barrel 1 of the tool. For this purpose I prefer to provide a plurality of substantially radial cutting blades 8 which extend downwardly from the lower end of the shoe, and the side of the shoe is preferably provided with reaming blades 9, the outside edges 10 of which are in substantially circumferential alignment with the outside cutting edges 11 of the cutting blades 8.

In Figure 1, I have illustrated the reaming blades 9 as being in the same plane with the smaller diameter than the barrel l, an annular space 12 will be formed all around the core, down which the circulating water may pass toward the shoe. The presence of this annular space or passage 12, insures that the packing of the hard core can not interfere with free passage of water down to the shoe at any time. The tool is constructed with means for projecting this annular stream at a high velocity against the side of the core, and this means is preferably located in, and constructed as a part of the shoe 4, For this purpose. the shoe is preferably formed with a tapered or conical opening 13. At the point where the core passes into the shoe, the area of the space between the side of the core and the tapered bore of the shoe, is relatively small, and hence, at this point the flow of the water acquires a relatively high velocity, having the direction of the arrows indicated in Figure 1. This produces a very eilicient eroding or washing action of the water on the core, effectively carrying away the relatively soft parts of the core.

In order to center the core in the barrel 1, I prefer to employ a core guide 14, which, in the present instance, consists of a tube or sleeve of any suitable construction, which will retain the solid parts of the core, but which will promote free circulation of water through the solid parts of the core. In other words, the guide 14 is preferably formed of suiciently heavy gauge to support and center the hard core, and is pro- `vided with perforations 15 facilitating circulation of the water. The upper end of this tube 14 is open.

Suitable means is provided for centering this core guide and supporting the same above the shoe. In the present instance, the shoe may be provided with inwardly projecting lugs 16 on which the lower end of the core guide 14 rests. The core guide is also provided with a plurality of laterally projecting ribs 17 which extend longitudinally at its upper and lower ends, and these ribs center the guide in the barrel 1.

In order to enable a hard core to be cut off and removed with the drill string when desired, I provide the tool with means for engaging the side of the core, and constructed so that this means will permit free, relative upward movement of the core through the tool, but which will operate to engage the side of the core upon a relative upward movement of the tool with respect to the core. Any suitable means may be employed for this purpose, but I prefer to employ means of the type illustrated in Figures 1 and 7.

The means illustrated in Figure 1 involves the use of a plurality of loosely mounted dogs which are preferably disposed in two sets, the upper set being shorter than the lower set. These dogs are preferably mounted in the lugs 16 of the shoe, and each dog is mounted in a corresponding socket or pocket 18 cut in the inner face of the lug. The dogs 19 of the lower set are preferably considerably longer than the dogs 2O of the upper set. These dogs are all pivotally mounted on suitable pins 21 and each dog is formed with a substantially cylindrical hub 22 that rests against the finished seat 23, to take the thrust of the dogs olf of the pins 2l.

When a core 24 (see Fig. 5) is passing through the shoe, the dogs assume the upwardly inclined position illustrated in Figure 5.

When it is desired to cut out a solid core to enable the drill string to be pulled, the drill string will be subjected to an upward strain which will jam the sharpened tips 25 of the dogs, into the side of the core. If the drill is now rotated with this upward strain, the dogs will cut away the material of the -core as indicated by the cuts 26 and 27. The lower dogs 19 are relatively long, and by reason of their great length, they might not commence to cut immediately into the side of the core when the upward strain is set in the drill string. However, as scon as the upper dogs 20 have cut a sumcient deep cut 26, the dogs 19 will fall down into a more nearly horizontal position, enabling them to bite effectively into the material of the core and increase the depth of the cut 26 substantially as indicated in Figure 6.

There may be as many of the dogs 19 and 20 as desired. In the present instance, I have illustrated three dogs in each set, located at 120 apart. In the present instance, these dogs are in vertical alignment with each other, but if desired', the dogs of the upper set may be staggered with relation to the dogs of the lower set. This staggered relation would increase the effectiveness of the dogs in retaining broken,- hard material in the core, and would also assist in retaining cores of gravel or similar material.

In Figure 7 I illustrate another type of corecutting means which consists of a plurality of tapered slips such as the slip 28. Theseslips are guided in sockets 29 on inclined guides such as the guide 30. These guides 30 converge toward the axis of the drill in a downward direction. The inner side of each slip is formed of inclined teeth 31. It is evident that slips of this type will permit free, relative upward movement of the core, but if an upward strain is placed on the drill string, they will immediately jam against the side of the core, and when the drill string is rotated, they will cut into the core and enable it to be broken off.

If desired, the upper end of the core guide can. be supported on the upper sub. This construction is illustrated in Figure 4, in which 5 indicates the upper sub. This sub is provided with a bearing opening 32 which receives the tubular neck 33 of a collar 34, the lower end of the collar being threaded into the upper end of the core guide 141.

The upper end of the neck 33 is provided with a nut 35 which can be screwed up tight on its thread 36, and provided with sockets 37 for a spanner wrench.

In the operation of this tool the circulating water passing down the annular passage 12 around the core, is projected at a high velocity at the base of the shoe against the side of the core, exerting a very effective scouring action carrying away all but the hard parts of the core. The body 1 of the tool therefore accumulates only the hard portions of the core that is being taken, and this enables the drill to be used for a relatively long period without pulling the drill string.

The means employed such as the dogs 19 and 20, or the slips 28, permit the core to pass relatively upwardly into the barrel 1 of the drill. If it happens that the drill string must -be pulled while the shoe is working in rocky formation,

this can be accomplished by subjecting the drill stringto an upward strain and continuing the rotation while under the strain. This enables the dogs 19 and 20, or the slips 28 to cut into 1 the score, reducing its area sufficiently to enable it to be dislodged by an up-jar on the string.

As the circulating water comes down through the passage 7, it comes directly upon the upper end of the core, thereby giving a thorough washing action, operating to dissolve and carry off the softer parts of the core through the perforations 15 in the core guide. The solid`matter such as mud and sand in this water, assists the eroding and scouring action that takes place at the choked lower end of the shoe where the water is projected against the side of the core and passes out of the shoe.

It will be evident that the dogs 19 and 20 perform the function of supporting the core as well as enabling it to be cut into `and broken ofi. If the core is of broken material or gravel, the dogs, when the drill string ispulled, will assume a nearly horizontal position and retain the core as the drill string is being pulled.

It is understood that'the embodiment ofthe ceive the core, said drill having an annual wall and having a plurality of dogs movably mounted in the same for engaging the side of the core, said dogs including a set of relatively short dogs and a set of relatively long dogs located at a lower level than the short dogs and mounted independently of the short dogs, said dogs cooperating when the drill is rotated to form cuts of y diierent depths in the side wall of the core, the longer dogs operating to increase the depth of the cut formed by the shorter dogs.

2. A rotary core Adrill having an opening to receive the core, said drill having an annular wall with a plurality of sockets with curved faces extending into the annular wall from its inner face, and forming curved shoulders on the bottoms of said sockets, rigid dogs mounted in the sockets extending upwardly in an inclined direction to engage the side of the core, and cooperating with the drill when the same is rotated to cut around the side of the core upon an upward movement of the drill relative to the core, said dogs having substantially cylindrical hubs resting against the bottoms of said stockets and imparting the downward thrust of the dogs through the curved faces of the hubs against the curved shoulders of the sockets.

3. A rotary core drill having, an opening to receive the core, said drill having an annular wall with a plurality of pockets therein extending into the same from the inner side and having a plurality of dogs movably mounted in the same for engaging the side of the core, said dogs 'including a set of relatively short dogs and a set of relatively long dogs located at a lower level than the short dogs and mountedindependently of the short dogs, pins securing said dogs in their corresponding pockets, said dogs having cylindrical hubs received in said pockets, thrusting against the same, and cooperating when the drill is rotated to form cuts yof different ydepths in the side wall of the core, the longer dogs operating to increase the depth of the cut formed by the shorter dogs.

4. A rotary core drill having an opening to receive the core, said drill having an annular wall with a plurality of sockets with curved faces on their. outer'sides extending into the annular wall from its inner face, and forming shoulders on the bottoms of said sockets, rigid dogs mounted in the sockets extending upwardly in an inclined direction to engage the side of the core and cooperating with the drill when the same is rotated, to cut around the side of the core upon an upward movement of the drill relative to the core, said dogs having substantially cylindrical mamas hubs resting against the curved inner faces of the sockets, said shoulders receiving the down'- ward thrust of said dogs, and pins mounted in the annular Wall and passing through the hubs of the dogs for retaining the same in their sockets.

JESSE C. WRIGHT. 

